Half-Wave, Full-Wave Rectification, and Zener Regulated Power Supply Report

Discussion in 'Electronics & Electrics' started by mbowen89, Oct 18, 2009.

  1. mbowen89

    mbowen89 Member

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    I just thought I would share this report I decided to wait until 3-5am in the morning to do the day of submission. It's a pretty basic report (my first one as a EET that is this in-depth actually... for my Analog Circuit Analysis class). It's not that in depth, just the basics of rectification and some zener diode action :)

    Tell me what you think! There are some things I could improve on it I'm sure, but I guess we shall see what my prof says with his red pen. :lol:


    Hopefully this link works: http://docs.google.com/fileview?id=...DItNmQxZS00YzRjLWE5NmUtOWEyNjM4NzllNmI4&hl=en
     
  2. Odje

    Odje Member

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    Can you now explain the limitation of a zener diode regulated supply?
     
  3. OP
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    mbowen89

    mbowen89 Member

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    My understanding of the zener diode is pretty bad actually.

    From what I do think I understand though, one of the biggest limitations of the zener regulated supply is that the zener can only handle so much current and power, as well it's a fixed voltage, am I correct? I used a zener that did 6.2V out. You would need to use a different zener if you wanted a different voltage, and also if you needed more power. I'd also say a zener has a lot larger ripple than a regulator. The zener also has dropout...

    Is most of that right? Anything else?

    We also used voltage regulators, but that wasn't included in this report for some reason... I don't know why my prof didn't want it.
     
  4. Odje

    Odje Member

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    Here are a few keywords for you to elaborate on:
    • Efficiency
    • Source Impendence

    The same keywords apply to any supply.

    The ripple is from the supply feeding the Zener shunt regulator. Linear and switchmode supplies have dropout too. Most applications do not require a variable supply. There are plenty of Zeners with different forward voltage drops.
     
    Last edited: Oct 18, 2009
  5. LethalCorpse

    LethalCorpse Member

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    Why would you say that?
     
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    mbowen89

    mbowen89 Member

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    How much ripple is there on Vout when you use a zener compared to a voltage regulator?

    The LM340-5 VR has a ripple rejection of 80 dB.

    In my simulation with the zener, the output had 2mV pk-pk ripple.



    So, my statement that a VR is handy because you can use the LM340-5 VR for example, and by using a different R2 resistor, get a different Vout is not very good? Because you can just buy a zener with a different dropout...?


    I may be wrong, but I had gathered that a VR was preferred over a zener. Different applications require different things obviously... so when would a zener be preferred over a VR? What's the efficiency of a zener in comparison?

    We haven't talked about source impedance... or even linear or switching supplies.
     

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